R. Zhang, X. F. Xiao, Q. L. Tai, H. Huang, J. Yang and Y. Hu (2012) Preparation of lignin-silica hybrids and its application in intumescent flame-retardant poly(lactic acid) system. Journal/High Performance Polymers 24 738-746. [In English]
Web link: http://dx.doi.org/10.1177/0954008312451476
Keywords: Intumescent flame retardant, lignin-silica hybrids, poly(lactic acid), ammonium polyphosphate, thermal stability, POLYPROPYLENE COMPOSITES, AMMONIUM POLYPHOSPHATE, THERMAL-DEGRADATION, POLYLACTIDE, BLENDS, PHOSPHATE, BEHAVIOR, AGENT
Abstract: Lignin-silica hybrids (LSHs) were prepared by sol-gel method and characterized by Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). LSH and ammonium polyphosphate (APP) were added into poly(lactic acid) (PLA) as a novel intumescent flame-retardant (IFR) system to improve the flame retardancy of PLA. The flame-retardant effect of APP and LSH in PLA was studied using limiting oxygen index (LOI), vertical burning (UL-94) tests and cone calorimeter. The thermal stability of PLA/APP/LSH composites was evaluated by thermogravimetric analysis (TGA). Additionally, the morphology and components of char residues of the IFR-PLA composites were investigated by SEM and XPS. With the addition of APP/LSH to PLA system, the morphology of the char residue has obviously changed. Compared with PLA/APP and PLA/APP/lignin, a continuous and dense intumescent charring layer with more phosphor in PLA composites is formed, which exhibits better flame retardancy. All the results show that the combination of APP and LSH can improve the flame-retardant property and increase the thermal stability of PLA composites greatly.